Design of dc link current observer for a 3-phase active rectifier with feedforward control

This paper describes a high performance current controlled three-phase unity power factor active rectifier. A second order current observer measures the dc link current drawn, which is then fed forward to a current regulator. A fast feedforward control scheme has been implemented without requiring actual dc link current sensors or communication channels, and is a control solution for common dc bus systems with multiple inverter driven loads. In addition, a novel method to estimate the value of the dc link capacitance is described in this paper. Both simulation and experiment have been conducted to investigate the performance of the active rectifier control, and excellent results show the validity of the proposed control model.